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shooky56
recumbent guru

USA
545 Posts

Posted - 09/22/2015 :  20:23:59  Show Profile  Reply with Quote
Haven't done much the last few. Had 3 days out racing and "caught something" that, in addition to a few normal puny symptoms seems to have given me dropsy lol. Felt a bit better today and worked on the nose. Still wanting to find out if the nose will be dimensionally correct so I cut a rib and stuffed it in to force the nose into the shape viewed on the screen.

Wanted to add something for Daryl. Here was the plastic for the disc covers from USPlastics:

Item: 43331 $10.39 .030" Thick High Impact Styrene Sheet 40" X 72"

Haven't made covers yet but it looks like it'll work and is plenty big enough for the 700s too (you had wondered).

The plastic I currently have on my front is NOT THIS but close, below is the FRP version. Couldn't find the non-reinforced version on-line. Same resin just no fiberglass. The young man who suggested it said they have it in FRP version and non-reinforced both. Of course I wanted the lighter and thinner stuff.

http://www.menards.com/main/paint/paneling-planking/paneling/4-x-8-textured-white-fiberglass-reinforced-plastic-wall-paneling/p-1503821.htm
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Speedbiker
human power expert

USA
3761 Posts

Posted - 09/22/2015 :  21:42:10  Show Profile  Reply with Quote
That's the stuff. Covers I made in 2012 still look great. I think I paid $9 a sheet way back then.
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shooky56
recumbent guru

USA
545 Posts

Posted - 09/23/2015 :  21:23:22  Show Profile  Reply with Quote
Finally got my Coro nose mounted. This one is supposed to be correctly sized to fit my foot box. I tried to make it take the shape as correctly as possible but I still barely ticked the heel.

It finally dawned on me that I hadn't actually checked to see how the clearances worked for so few sides. That was the issue. Although I had roughly 1/4" slop all the way around my footbox with 200 strips (the default), with only 10, my feet didn't quite make it. Toes and heels were protruding.

Noticed another thing. With 10 sides, the heels and toes aligned in the middle of a flat surface, the worst possible way to fit them. With 12 sides it looks like corners line up better with the heel and toe.

But boy oh boy that 700 is low. Anything that clears my knees is about exactly eye level. Hard to view over the cowling. Probably have to scoot back to get my head higher. Probably lot's of builders have had to deal with the same thing.
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Speedbiker
human power expert

USA
3761 Posts

Posted - 09/23/2015 :  23:17:04  Show Profile  Reply with Quote
Replace those top panels with PETG....
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shooky56
recumbent guru

USA
545 Posts

Posted - 09/24/2015 :  03:27:43  Show Profile  Reply with Quote
May do that, thanks Thom.
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shooky56
recumbent guru

USA
545 Posts

Posted - 09/24/2015 :  14:57:13  Show Profile  Reply with Quote
Finally made some decent mounts for the cone and the fit is almost exactly what I saw on the screen so that's a warm fuzzy that you'll get what expect if you use the software to build your shell.

There are still a few things I'd like to fix in the current version then drop work on it and go back to the parallel release that was "all 3D all the time".

The most prominent problem is the ribs don't work for small side counts. When it should be a decagon (10-sided) for example it lops off the top of the rib. Working to fix that and will release it when it's ready.

On the bright side, my mile repeat workout averaged 23.1 mph for the entire ride. That's about what I was doing on my better weggie rides in recent years so the trike w/cone has caught the Cervelo!

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shooky56
recumbent guru

USA
545 Posts

Posted - 09/29/2015 :  09:47:24  Show Profile  Reply with Quote
Just a status report. Something around 5:50 this morning (neighbor gal and I skipped our morning walk due to rain so I was up early with no where to go but to the keyboard), I got the straight sided ribs printing (for fitting inside of CoroPlast shells). Still some details to clean up but it's a lot closer to release.

Also in the rounds. I pushed one of the smooth ribs up into my 40" nose cone to true the nose's cross sectional shape. The foot box was designed to be very tight and it is. My left tightening strap rubs slightly for a piece of the bottom of the stroke. It's unnoticeable except I could hear something and had to look. After 100ish miles there is now a telltale grayish smear where the Coro is discoloring. Shifting the bottom of the shell 1/4" left would fix it but I already have the info I need namely these shapes are dangerously close to being correctly sized.

My next step is to start another Coro shell. Who knows? This one may stay because cold weather is approaching but my mindset is another direction. My plans are to smear 2 part foam on the Coro and sand it for a plug. To that end I'd want the ribs inside to enforce shape integrity, probably plywood to give some mounting strength. Part of the details of the software are adding the alignment holes to the multi-sided ribs like the smooth ones have. If the Coro shell is big enough to be ridden the foaming will make it a big large. Since my goals are more along the lines of what Tony does (long trips), a bit of space won't bother me. Doesn't mean I won't race it but my intent is not now, nor ever has been to build a racer. The only hook to all that is ... you know? a BM cap sounds like a neat goal. Of course that WOULD take a dedicated machine. Ain't dead yet, who knows?

---------------

Also have some ride reports. My old throw-away poster board nose smashed all my trike records. I only have one out and back course (18 miles). I do not do a rolling U-turn lest I kill myself but rather stop the clock, make a leisurely U-turn, get back up to 20ish mph, restart the clock. Here are the numbers (all solo efforts of course).

Bare Trike: 20.1
Wheel Covers (all three): 20.7 (the rest of the times have the covers)
Posterboard 30 inch Nose: 21.9 (22.1 for a 24.1 loop course)
CoroPlast 42 inch Nose: 22.6





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Speedbiker
human power expert

USA
3761 Posts

Posted - 09/29/2015 :  10:20:33  Show Profile  Reply with Quote
Pull straps? Go clipless! I think Charlie started using them when he was 8. At 39 you should be fine, especially on a trike.
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warren
human power expert

USA
6119 Posts

Posted - 09/29/2015 :  15:01:26  Show Profile  Visit warren's Homepage  Reply with Quote
I think we are all 39 here...
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shooky56
recumbent guru

USA
545 Posts

Posted - 09/29/2015 :  15:20:34  Show Profile  Reply with Quote
Sorry for my ambiguity. The straps that tighten my shoes onto my feet. My shoes have tightening ratchet handles and the little gizmo on the left shoe rubs (it wasn't accounted for in the design). I snapped off the one on the right a month or two ago... it doesn't rub :)

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Speedbiker
human power expert

USA
3761 Posts

Posted - 09/29/2015 :  19:20:43  Show Profile  Reply with Quote
Who's idea was it to put big ski boot buckles on bike shoes?
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Larry Lem
human power expert

South Sandwich Islands
2524 Posts

Posted - 09/29/2015 :  20:25:01  Show Profile  Reply with Quote
The same people who thought it would be a good idea to put ski bindings on pedals.

Larry Lem
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Speedbiker
human power expert

USA
3761 Posts

Posted - 09/30/2015 :  01:20:58  Show Profile  Reply with Quote
That'll never work. Skis are too long.
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Larry Lem
human power expert

South Sandwich Islands
2524 Posts

Posted - 09/30/2015 :  07:44:59  Show Profile  Reply with Quote
I wonder if the development of toe-clipless pedals went from skis with ski bindings, to roller skis with ski bindings, to bicycles.

Larry Lem
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Upright Mike
human power expert

USA
3803 Posts

Posted - 09/30/2015 :  09:08:16  Show Profile  Reply with Quote
I never ski, put I am part Polish, again without the -ski last name
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darylhanger945
New Member

USA
54 Posts

Posted - 09/30/2015 :  09:13:41  Show Profile  Reply with Quote
Thanks Wayne for the info on the material for the wheel covers. I will have to work on my new covers this winter. (i am only 30)

Daryl
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shooky56
recumbent guru

USA
545 Posts

Posted - 09/30/2015 :  12:43:54  Show Profile  Reply with Quote
Welcome Daryl. Shoot I'll have 30 doubled down in a few months!
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shooky56
recumbent guru

USA
545 Posts

Posted - 10/02/2015 :  19:24:44  Show Profile  Reply with Quote
Getting closer for the long prints. To beat this dog to death, my problem was drawing long lines one way then back to the start (making one strip of a Coro shell). That method gave paper feed errors I found unacceptable.

So I'm re-writing the code to print a little bit of the lengths of several strips and slowly working from one end of the paper to the other printing all that fit on a 28" wide paper as it goes. This is similar to CNC codes. An intermediate piece of software loads the file I create then delivers codes to the banner printer. As seen below I print all the yellow portion then all the red, then green, etc. until we reach the end of the strips. The colors are just to help explain.

[URL=http://s1372.photobucket.com/user/shooky56/media/Recumbent%20Postings/Multi-Pass%20printing_zpsexbgmykh.png.html]
[/URL]
My first "full size" test went pretty well. I dropped a bit of the tail end and need to fix it and it isn't optimized. It always prints ONLY from left to right when I should print on the way back. Three strips took 12:48 seconds but they look good. The paper can still drift but the error is manifested differently. Before the error would result in the shell circumference shrinking by as much as 3 inches (losing 1 inch in diameter). With this re-write the paper can still drift but the errors manifest in the final product much differently. Basically the error shows up as a joined edges drifting. I did do the math but that's probably of little interest to most. Unless I goofed my worst errors only result shape distortions not volumetric distortions. The circumference error is (nearly) zero. There is also a length but it's something on the order of 1/8" in 10 feet.

So I'm happy with the errors and the way it prints A half-shell (one side) is all you need and that can be printed in under 30 minutes in full sized prints.

Also ran a couple little experiments but the winds here have been so strong I'm not sure my tests got a decent chance. One of them was a small tailbox. I'd pretty much gathered from reading similar efforts on this site that for a tailbox "go big or go home". Nonetheless I ignored all (only because it's easy to build a small one) and built a little one. Appeared useless. My next one will be from the shape off the software or else just the full coro shell (although I have to retro the steering to use a full shell).
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Speedbiker
human power expert

USA
3761 Posts

Posted - 10/02/2015 :  22:04:02  Show Profile  Reply with Quote
Go full or home home! Ha ha. Nice work.
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Speedbiker
human power expert

USA
3761 Posts

Posted - 10/02/2015 :  22:08:02  Show Profile  Reply with Quote
Here is the flat panel design we did years ago using a carved foam nose. Charlie set a (very)Jr speed record with this fairing with a (spun out) speed of 36+. He was 12 years old.http://www.recumbents.com/wisil/coslinger/club_racer.htm
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shooky56
recumbent guru

USA
545 Posts

Posted - 10/03/2015 :  04:40:18  Show Profile  Reply with Quote
Thanks Thom, very cool kit.

Charlie was flying!
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Grant-53
recumbent guru

USA
544 Posts

Posted - 10/03/2015 :  08:38:44  Show Profile  Reply with Quote
If the tail box is narrow compared to a rider's body width it will have little effect in my experience. I keep looking at the plastic mixing bowls in the housewares aisles for a nose piece.
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shooky56
recumbent guru

USA
545 Posts

Posted - 10/04/2015 :  08:15:20  Show Profile  Reply with Quote
Grant:
Bowls, hehe, I can relate man I can relate.
Tail Box, I didn't expect much from mine, pretty much got what I expected. About the most interesting little tidbit floating around in my head about tail boxes is from a link in here... lemme find it.

Toward the end of Nick Demma's review of the book "The Aerodynamics of Road Vehicles" he quotes.

"This confirms the idea of Wunibald Kamm. Kamm's conclusion was that you should find the point where the tail is half as wide as the maximum width of the vehicle and cut it off there. There is little benefit in having it extended beyond this point because the piece that you keep effectively tricks the air into thinking that the rest of it is there anyway."

My software doesn't support bob-tailing but the question raises some interesting concepts. At a Length-to-width of around 6 to 1, according to what I've read, skin friction starts overtaking the parasitic friction and you don't get much benefit beyond 6 to 1. I can't verify this but that almost surely assumes the standard teardrop where the fat part is 30% of chord length from the leading edge. Most forward facing riders have "laminar" bodies (whereby the fat part is 40% or more from the leading edge). Every shape I've studies is short of true L/D of 6 to 1. If the 5:1 ratios that really are out there were judged by the 30% rule, they are more like 3.5 or 4 to 1 (imagine a long wedge, its shape can be 5:1 but we all know "that aint right"). But if we start the taper back more gently behind the rider and bob-tail the rear, it would emulate moving the thickest part "virtually forward" and may achieve better drag ratios. Now I don't know if any of that is legit or BS but it sure has my curiosity up...

And there's more BS on top of that too. The world besting designs have moved the "fat part forward" compared to the de-facto Varnas that dominated so long. That said, the Varna shell is accessible thanks due to molds. Therefore is relatively easy to copy and, despite 30 person efforts has only been bested by a few mph. Of course that matters to the BM guys but to us common folk who only want practical streamlined vehicles, Georgi is truly a design genius.

Perhaps with Winter coming in and me doing my usual hibernation I'll add a bob-tail possibility to the software so we can run some CFD sims on it.

Anyway I've been totally fascinated by aerodynamics since I was old enough to know things flew. Mom knew there was one and only one toy I ever wanted, the 25 cent rubber band plane from Ben Franklin's five and dime store.

I'm still 5 years old putting Scotch tape on the trailing edges of the wings just to see what happens... just older and the planes cost more...
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shooky56
recumbent guru

USA
545 Posts

Posted - 10/04/2015 :  09:01:38  Show Profile  Reply with Quote
So I got my multi-print working and am bitterly disappointed. That printer still drifts too much. With all the little forward backward movements, it drifted two inches side to side during the run. So I'm going to revisit making guides to force the paper aligned and true. Last effort crashed and burned as the paper crumpled up in the guides but have another idea, should have it working today and mocking up my first full shell, almost one year since I started writing the software.
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Speedbiker
human power expert

USA
3761 Posts

Posted - 10/04/2015 :  10:49:02  Show Profile  Reply with Quote
What's a "five and dime"?

Ha ha ha....
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